What is a TCP three-way handshake?

Interviewers ask about the TCP three-way handshake to assess your technical knowledge and understanding of networking protocols. This fundamental concept is crucial for anyone working in IT, networking, or cybersecurity. Your ability to explain the process demonstrates your grasp of the underlying principles of communication over networks, which is vital for troubleshooting and optimizing network performance.

A good response should articulate the three steps of the TCP handshake: 'first, the client sends a SYN packet to the server to initiate a connection; second, the server responds with a SYN-ACK packet to acknowledge the request; and third, the client sends an ACK packet back to confirm the connection is established. This process ensures that both sides are ready to communicate and helps in maintaining data integrity. For instance, 'When I set up a network for a client, I always ensure that this handshake occurs correctly, as it’s critical for the reliability of data transmission.'